Runoff of nutrients and faecal micro-organisms from grassland after slurry application

摘要

The application of slurry on perennial grass is becoming more normal on Finnish dairy farms, because the farms mainly have perennial grass leys and less cereal. However, the effect of recurrent slurry application on the eutrophication and hygiene ofsurface waters is not well known. We have therefore studied the phosphorus and nitrogen runoff and levels of faecal micro-organisms in surface runoff at experimental plots with perennial grass. An eight-plot experimental field (0.34 ha) was located on aclay soil at Jokioinen, southern Finland. The slurry applications were done the in summer and autumn of 1998-2000. The experimental areas were fertilised according to agricultural practice with cattle slurry, either surface-spread or injected into the soil. The control was mineral fertilisation on the soil surface. The runoff was normally low. However, in the autumn of 1998, the saturated soil and heavy rainfalls immediately after the slurry application increased the loads of nutrients and faecal micro-organisms from the treatments 1 and 2. The levels of total runoff phosphorus and nitrogen were 2.7 and 7.8 kg ha~(-1), respectively, in the surface-spread plots in the winter of 1998-1999.